Brake slack-adjuster.



No. 7 0,778. PATENTED MAY 24,1904.

' .P. L. CLARK.

' BRAKE SLACK ADJUSTER.

APPLIQATION FILED SHIT. 6, 19.01. I

i i i no MODEL.

NW N I TION on MISSOURI.

UNIT STATES;

Patented May 24,1904.

PATENT OFFICE.

PENNSYLVANIA, Assleuon TO THE MISSOURI, A ooRPoRA- BRAKE SLACK-ADJUSTER. A

SPECIFICATION forming part of Letters Patent No. 760,778, dated May 24, 1904.

Application filed September 6,1901. .SerialNo. 74,536. (No model.)

T0 alZ 1071 0711, it-mn y concern.- I

Be it knownthat I, F ANCIS L. CLARK, a citizen of the United States, residing at Pittsburg, .county of Allegheny, State of Pennsylvania, have invented or discovered a certain new and useful Improvement in Brake Slack- Adjusters, of which improvement the following is a specification.

- My invention relates to slack-adjusting the brake-shoes, stretching ofthe rigging, orv

other causes, may be automatically taken up,

so as to preserve a uniform travelof the brakepiston.

My invention comprises an extensible pushbar made in sections hav ng-a'slidlng ratchet connection, the end of one sectlon beln g adapted to operate loosely in the ordinary hollow piston-rod of the, brake cylinder and the other section being connected to a brake-opcrating lever. 3 I a g It also includes a spring which is secured to a stationary or fixed support and adaptedto be operated by an excessive travel of the brake-piston, so th atlupon release of the brakes the spring will effect a relative movement of the sections of the push-bar.-

Other features 0f,;my invention will appear hereinafter, as the construction is more fully described. s 4

In the accompanying drawings, which illustrate an embodiment of my invention, Figure 1 is a vertical longitudinal section of my improvement shown applied to the rear end of a brake-cylinder. Fig. 2 is a view showing the brake-cylinder in plan and the push-bar in horizontal section; Fig. 3 is atransverse section taken on the line 00 a; of Fig. 1. Fig. 4 is a transverse section taken on the line y y of Fig. 2; and Fig.5 is .a rear end elevation of the brake-cylinder, the push-bar being shown in section.

My improvement is particularly adapted to be used in connection with that form of brakel cylinder inwhich the piston is provided with a hollow or tubular piston-rod extending through the rear head of the brake-cylinder and adapted to receive the loose push-bar of the brake-rigging, which construction is that now ordinarilyemployed. on freight-cars.

- Referring now to the drawings, the piston tubular rod 2, extending out through the rear head of the cylinder, and in thisis inserted the inner end of one section, 3, of the exten-- siblepush-bar, the other'section, 10, of which lever of the brake-rigging. The push-bar may be constructed with any adjustable slidpreferred arrangement I haveshown the outer end of section 3-extending into ahollow portion of the section 10, forminga sort of telescopic connection, this portion of section 3 being provided with ratchet-teeth 11, adapted of the push-bar. In-the construction as shown there are two pawls engaging teeth on opposite sides of the ratchet-bar; but it isobvious that one or ;any number of pawls may be used, as desired. Springs-14 keep the pawls normally in engagement with the teeth of the ratchet-bar. j

On the cylinder-head is bolted or otherwise secured the casing 55, containing a rod 7 having a head 8 ,and a spring 6, acting between the head 8 of the rod and the opposite end of the casing. The rod 7 extends out through an opening in the casing and loosely through an opening in an arm 4:, carried by the section 3 of the push-bar, and is provided withadjustable nuts 9 at a suitable distance fronathe brake-cylinder. The nuts 9 are adjusted at not engage therewith during the normal travel of the brake-piston, but when, owing to wear makes a longer stroke than normal the armi will strike against the nuts 9 and carry the rod along with the push-bar until the brakes are set. This movement will operate to cornof the brake-cylinder 1 is provided with the ing connection between thesections; but as a to be engaged by-pawls 13, pivoted on pins. 12 in side openings 15 of the outersection 10' such position on the rod 7that the arm 4 will of the brake-shoes or other causes, the pistonis adapted to be pivotally connected to the press the spring 6 between the head 8 and the opposite end of the casing 5. Then when the brakes are released and the brake-piston spring moves the hollow piston-rod 2 back toward its release position a slight distance in advance of the following push-bar the spring 6 will have an opportunity to expand and carry the head8 against the end of its casing. At the same time, since the nuts 9 are bearing against the arm 4, this movement will cause the section 3 of the push-bar to move inward more rapidly than the section 10 is moved back by the relaxation of the brake-rigging,

and thus the ratchet-bar will be carried over the pawls one or more notches, according to the extent of the excessive travel of the brakepiston. By this means the push-bar is automatically elongated and the slack of the brakerigging eliminated.

It .will be evident that 'various other arrangements of the actuating-spring 6 may be used; also, that it may be secured to a fixed part of the car body or frame instead of the brake-cylinder; but I prefer the construciton shown, as it renders the operation of the spring more certain and accurate and protects the same from injury.

Having now described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. In a brake slackadjuster, the combination with an extensible push-bar formed of adjustable sections havinga sliding ratchet connection, of a spring operating between a fixed support and one section of the push-bar.

2. In a brake slack-adjuster, the combination with an extensible push-bar formed of adjustable sections, of a spring separate from that of the brake-piston normally bearing on a fixed support and adapted to cause a relative movement of said sections.

3. In a brake slack-adjuster, the combination with an extensible push-bar formed of adjustable sections, of a spring secured to the exterior of the brake-cylinder and adapted to cause a relative movement of the-sections.

4. In a brake slack-adjuster, the combination of an extensible push-bar formed of adjustable sections, and a spring adapted to be compressed between a fixed support on the brake-cylinder and one of the adjustable sections when the travel of the brake-piston is excessive.

5. In a brake slack-adjuster, the combination with an extensible push-bar formed of adjustable sections, of a spring for causing a relative movement of said sections and having a fixed support, and means connected to one of said adjustable sections for imparting a stress to the spring when the travel of the brakepiston is excessive.

6. In a brake slack-adjuster, the combination with an extensible push-bar formed of adjustable sections, of a spring for causing a relative movement of said sections and having a fixed support on the brake-cylinder, and means connected to one of said adjustable sections for giving a stress to said spring when the travel of the brake-piston is greater than normal.

7. In a brake slack-adjuster, the combination of an extensible push-bar formed of adjustable sections, a spring-actuated rod supported by the brake-cylinder and having adjustable nuts, and an arm carried by one of the adjustable sections of the push-bar for engaging said nuts upon an excessive travel of the brake-piston.

8. In a brake slack-adjuster, the combination with'an extensible push-bar formed of adjustable sections, of a spring-actuated rod having adjustable nuts, a casing for said spring secured to the brake-cylinder head, and an arm carried by one section of the push-bar for engaging said nuts when the travel of the brake-piston is excessive.

9. In a brake slack-adjuster, an extensible push-bar formed of adjustable sections having a sliding ratchet connection, two pawls pivoted on one section and engaging teeth on opposite sides of the ratchet-bar of the other section, and a spring for causing a relative movement between said sections.

In testimony whereof I have hereunto set my hand.

FRANCIS L. CLARK.

Witnesses:

J AS. B. MACDONALD, R. F. EMERY. 

